Liposomes

The marketing literature and packaging for many skin care products and treatments state that their formulas contain liposomes and list the presence of liposomes as being among their benefits. This leads many consumers to believe that liposomes are a particular type of active ingredient that improves the look and feel of the skin;however, this is a misconception. Liposomes are not active ingredients at all, but rather, function as a delivery method for the ingredients in a particular product.

A liposome is a vesicle or small bubble composed of phospholipids, fatty acids that contain phosphorous. Two layers of these phospholipids are found in a liposome, and a tiny amount of space exists between them. Sometimes called a membrane, this phospholipid bilayer does not dissolve in water and can be used to enclose any type of liquid materials.

The principle that led to the creation of liposomes comes from that of the cells in the human body. Each cell is covered with a cellular membrane, which keeps all of the organelles (the components that perform tasks inside of cells) protected and in place. The cellular membrane selectively allows materials to enter and exit the cells, allowing them to import nutrients and export the proteins, sugars and other molecules that they produce. Similarly to the cellular membrane, the liposome allows the materials inside of it to pass through gradually.

Liposomes were discovered in 1961 by Dr. Alec D. Bangham, a British doctor who specialized in the treatment of conditions that affect the blood. The discovery occurred when Bangham was testing a new electron microscope at the Babraham Institute in Cambridge, England. When he was preparing samples for testing, he added a special dye, intending to make them more readily visible under the microscope. To Bangham's surprise, the sample resembled human body cells when he examined them under intense magnification. His curiosity piqued, Bangham began to study the materials in the sample, and by 1964, had published the first study on liposomes.

The science for creating liposomes has evolved since Dr. Bangham's initial writings on the subject. Over the decades that followed, researchers and scientists have found ways to manufacture liposomes to deliver a multitude of ingredients throughout the body and to the skin. Work has also been done to reduce the size of the liposomes found in products. With the advent of nanotechnology (creating molecules of exceptionally small size) liposomes are now made so small that they are between 10,000 and 2,500 nanometers in diameter. These microscopic liposomes allow for greater absorption in the skin tissue, enhancing the effectiveness of the products that contain them.

In skin care products, liposomes can perform a number of important functions. A formulation that contains liposomes is excellent for delivering ingredients that must stay in contact with the skin tissue for prolonged periods of time, as the membranous vesicle holds its contents safely in place once the product is applied. This is beneficial in products used to lighten skin hyperpigmentation, protect the skin from oxidative damage and reduce signs of aging. Liposomes are also useful for delivering medications for treating fungal and bacterial skin infections.

Because liposomes do not dissolve in water, they are often used to protect the ingredients in skin care products from water. Sunscreens that contain liposomes are resistant to water, making them ideal for use for swimming and on humid days. Some types of waterproof mascaras, eye liners and eye shadows deliver their pigments with liposomes, so that they do not streak, smear or fade, even if the eyes water.

Studies have found that many skin conditions, such as extreme dryness or dehydration, respond better to prolonged exposure to low doses of active ingredients as opposed to one massive dose. To capitalize on the benefits of dispensing ingredients over time, many skin care companies offer time-release products, which give off small doses of their active ingredients typically over a 12 or 24-hour period. These products generally use liposomes to achieve these effects;the liposome allows only tiny amounts of the ingredients to leave the phospholipid bilayer at a time. As the liposomes release the ingredients, they slowly break down over the 12 or 24-hour time frame, allowing the skin to benefit from products without the need to continuously reapply.